The author introduces the reader to the essential qualities of Baroque art, telling how mannerism was finally supplanted by Caravaggio's naturalism and relating the new acceptance of sensual experience to a new curiosity about human psychology and the inner life. He discusses attitudes to antiquity and the profound effect of the Copernican revolution through which the artist's vision of light and time dramatically altered, to create a sense of infinite space coupled with an intensifying awareness of mutability and change. Throughout, he emphasizes this century's balance between the secular and the religious, an equilibrium which allowed spiritual or mystical qualities to permeate even the most apparently mundane of genre paintings, which is the great distinguishing feature of Baroque art.